为什么＆＃39;包含＆＃39;不工作？或者我做错了？

Question

目的：

1. 检查用户输入是否为字母
2. 检查它是否是元音或辅音
3. 检查字符串中是否有重复的字母

包含不返回任何内容或我使用错误

Scanner out = new Scanner(System.in);
    System.out.print("Please insert a text: ");

    String[] vowels = {"a", "e", "i", "o", "u"}; 
    String userInput = out.nextLine();
    char[] charUserInput = userInput.toCharArray();
    String temp = "";
    String temp1 = "";
    for (int i = 0; i <= charUserInput.length -1; i++){
        if (Character.isLetter(charUserInput[i])){
            if (Character.toString(charUserInput[i]).equalsIgnoreCase(vowels[0]) || (Character.toString(charUserInput[i]).equalsIgnoreCase(vowels[1]) ||
                    (Character.toString(charUserInput[i]).equalsIgnoreCase(vowels[2]) || (Character.toString(charUserInput[i]).equalsIgnoreCase(vowels[3]) || 
                            (Character.toString(charUserInput[i]).equalsIgnoreCase(vowels[4])))))){
                    if (!Character.toString(charUserInput[i]).contains(temp)){
                        temp += Character.toString(charUserInput[i]);
                    }
            }else{
                if (!Character.toString(charUserInput[i]).contains(temp1)){
                    temp1 += Character.toString(charUserInput[i]);
                }

            }
        }
    }
    System.out.println(temp);
    System.out.println(temp1);
    out.close();

Answer 1

看起来你倒置了条件：使用

temp.contains(Character.toString(charUserInput[i])) 

而不是

Character.toString(charUserInput[i]).contains(temp)